Difference between Distance and DisplacementDistinguish between Distance and DisplacementDistance is the length between two points or two places. It is a length covered by a body in motion. Distance is a scalar quantity because it has magnitude only. For example, a car moved 4 km. ‘4 km’ is the magnitude of the distance covered.Displacement is the length between two points in a specific direction. It is simply a distance covered by a moving body in a specific direction. Displacement is a vector quantity because it has magnitude and direction. For example, a car moving through 4 km towards north. ‘4 km’ is the magnitude of the displacement and ‘north’ is the direction of the motion of the car.Differences between distance and displacement

The SI Units of Distance and DisplacementState the SI units of Distance and DisplacementDistance and displacement have the same S.I unit which is Metre (m). other common units used to measure distance and displacement are Kilometre (km), centimetre (cm), millimetre (mm), miles and so on.

Speed and VelocityDifference between Speed and VelocityDistinguish between Speed and VelocitySpeed is the distance moved by an object per second. It is the rate of change of distance. It is obtained by dividing the distance moved by the objects to the time taken. Speed is a scalar quantity hence have magnitude only.

Velocity is the displacement per second. It is simply the speed of a body in a specific direction or the rate of change of displacement. Velocity is obtained by dividing the displacement to the time taken. Velocity is a vector quantity.

The SI Unit of Speed and VelocityState the SI unit of Speed and VelocityThe SI unit of speed and velocity the same namely metre per second (m/s). The other common unit are Kilometre per hour (km/h).Conversion between km/h and m/s.To change 1 km/h to m/s;1 kilometre is changed into metre by multiplying it with 1000 while 1 hour is changed into seconds by multiplying with 60 x 60 as shown in the equation below.

To change 1 m/s to km/h;1 m is changed into km by dividing it by 1000 while 1 sec is changed to hours by dividing it by 60 x 60 as shown below.

The Average Velocity of a BodyDetermine average velocity of a bodyAverage velocityis the average or mean value between initial velocity (U) and final velocity (V). It is also defined as the ratio of the total displacement to the total time.

The following are important terminologies related to velocity of a moving body;

MOTION IN STRAIGHT LINEMotion is the change of position of an object from one place to another. It is the study of the movement of a body from one point to another. It studies of all aspects of motion including distance and displacement, speed and velocity, acceleration and deceleration e.t. c.There are two types of motions;Circular motion- Is the motion of an object in a circular path. Examples; Motion of the electron around the nucleus of an atom, Revolutionary movement of the earth around the sun, Motion of a car around a cornered road.Linear motion- Is the motion of an object in a straight-line path. Examples; A fruit falling from a tree, a stone thrown vertically upward, a bus moving along a straight road.Distance and DisplacementDifference between Distance and DisplacementDistinguish between Distance and DisplacementDistance is the length between two points or two places. It is a length covered by a body in motion. Distance is a scalar quantity because it has magnitude only. For example, a car moved 4 km. ‘4 km’ is the magnitude of the distance covered.Displacement is the length between two points in a specific direction. It is simply a distance covered by a moving body in a specific direction. Displacement is a vector quantity because it has magnitude and direction. For example, a car moving through 4 km towards north. ‘4 km’ is the magnitude of the displacement and ‘north’ is the direction of the motion of the car.Differences between distance and displacementBASIS FOR COMPARISONDISTANCEDISPLACEMENETMeaningDistance refers to the amount of space between two points, measured along the actual path, linking them.Displacement refers to the amount of space between the two points, measured along the minimum path linking them.What is it?Length of the total avenue traversed by the body.Least distance between starting and ending point.QuantityScalar QuantityVector QuantityInformationGives complete information of the route followed by the body.Does not give complete information of the route followed by the body.TimeDistance can never decrease with time.Displacement can decrease with time.ValuesPositivePositive, Negative or ZeroUnique pathNoYesDenoted bydsFormulaSpeed × TimeVelocity × Time Test YourselfThe SI Units of Distance and DisplacementState the SI units of Distance and DisplacementDistance and displacement have the same S.I unit which is Metre (m). other common units used to measure distance and displacement are Kilometre (km), centimetre (cm), millimetre (mm), miles and so on. Test YourselfComplete and Continue Speed and VelocityDifference between Speed and VelocityDistinguish between Speed and VelocitySpeed is the distance moved by an object per second. It is the rate of change of distance. It is obtained by dividing the distance moved by the objects to the time taken. Speed is a scalar quantity hence have magnitude only.Velocity is the displacement per second. It is simply the speed of a body in a specific direction or the rate of change of displacement. Velocity is obtained by dividing the displacement to the time taken. Velocity is a vector quantity. Test YourselfThe SI Unit of Speed and VelocityState the SI unit of Speed and VelocityThe SI unit of speed and velocity the same namely metre per second (m/s). The other common unit are Kilometre per hour (km/h).Conversion between km/h and m/s.To change 1 km/h to m/s;1 kilometre is changed into metre by multiplying it with 1000 while 1 hour is changed into seconds by multiplying with 60 x 60 as shown in the equation below.To change 1 m/s to km/h;1 m is changed into km by dividing it by 1000 while 1 sec is changed to hours by dividing it by 60 x 60 as shown below. Test YourselfThe Average Velocity of a BodyDetermine average velocity of a bodyAverage velocityis the average or mean value between initial velocity (U) and final velocity (V). It is also defined as the ratio of the total displacement to the total time.The following are important terminologies related to velocity of a moving body;Initial velocity (U)– is the velocity of a body at the start of observation.Final velocity (V)– is the velocity of a body at the end of observationUniform or constant velocity- Is the velocity where by the rate of change of displacement with time is constant.Absolute velocity- is the actual velocity of a moving object recorded by a stationary observerRelative velocity- is the velocity of a moving object recorded by a moving observer.Instantaneous velocity- is the velocity of a moving object recorded at any time. Test YourselfComplete and Continue AccelerationAcceleration is the rate of change of velocity. It is the change in velocity per unit time. It is obtained by dividing the change in velocity of a moving body to the time taken. Acceleration is a vector quantity.

Velocity Time-graphInterpret velocity time-graphThis is a graph drawn to represent motion of a body. Velocity is represented by the vertical axis while time is represented by its horizontal axis. Consider a body accelerating uniformly from rest to a certain velocity v within time t. This can be represented graphically as shown below;

In the above graph, the body attained a velocity of 8m/s within 2 seconds. It also attained 16m/s within 4 seconds. It reached its final velocity (v) 20m/s at 5 seconds. The initial velocity (u) was 0m/s.

Distance travelledThe distance covered by a body can be calculated from a velocity-time graph by calculating the area covered under the curve/graph. In this case the area under the velocity-time graph is always the area of the triangle.Consider the shaded area (triangle OBC) on the above graph;

AccelerationAcceleration can be calculated from the graph by calculating the slope of the graph. Slope of the velocity-time graph is obtained as the ratio of the change in velocity to a respective change in time.

Consider again the shaded region of our previous graph in where by velocity changed from u =0m/s to v =12m/s along vertical axis BC and the time changed from t₁ =0s to t₂ =3s along horizontal axis OB.

Therefore, the body accelerated by 3m/s² by changing its velocity from 0m/s to 12m/s within 3s

A body is a said to accelerate when its velocity is increasing with time. That is, the final velocity v, is always smaller to the initial velocity u. See the below examples;